Attraction and unbinding of like-charged rods

TL;DR

This paper combines Molecular Dynamics simulations and strong-coupling theory to study the interactions of like-charged rods, revealing attraction at high electrostatic coupling and predicting unbinding at a specific Manning parameter threshold.

Contribution

It introduces a combined simulation and theoretical approach to analyze electrostatic interactions, identifying conditions for attraction and unbinding of like-charged rods.

Findings

Attraction occurs at high Manning parameters.

Unbinding threshold is at Manning parameter 2/3.

Equilibrium separation is on the order of the Gouy-Chapman length.

Abstract

We investigate the effective interaction between two like-charged rods in the regime of large electrostatic coupling parameters using both Molecular Dynamics simulation techniques and the recently introduced strong-coupling theory. We obtain attraction between the rods for elevated Manning parameters accompanied by an equilibrium surface-to-surface separation of the order of the Gouy-Chapman length. A continuous unbinding between the rods is predicted at a threshold Manning parameter of 2/3.